This study investigates the multifaceted factors influencing adjustment to prostate cancer among older men in Esfahan, Iran, using the social ecological model (SEM) as a guiding framework. We employed a qualitative approach, conducting semistructured interviews with 19 men diagnosed with prostate cancer, aged 63 to 92 years (mean age = 71), and six key informants, including spouses and health care professionals. We thematically analyzed the data to identify challenges and facilitators in the intrapersonal, interpersonal, and environmental domains of the SEM. The findings revealed a dynamic interplay of factors shaping the adjustment process. Intrapersonal challenges included physical degeneration, psychological distress, stigma, and role reversal, countered by coping strategies such as adopting healthy habits and spirituality. Interpersonal dynamics encompassed family strain and denial, yet the presence of familial support and self-care significantly enhanced adjustment. On an environmental level, financial burdens and health care barriers posed significant challenges. The study furthermore highlighted critical issues like "dysmedication" and "body occupation" which impede effective coping. A complex network of personal, relational, and systemic factors influences the adjustment to prostate cancer among older Iranian men. We urgently need tailored, culturally sensitive interventions to address health care inequities, alleviate economic pressures, and enhance psychosocial support networks, thereby empowering older adults to navigate this challenging journey with greater resilience and dignity.